var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
//引入
const {
  createProxyMiddleware
} = require('http-proxy-middleware');
const options = {
  target: 'http://127.0.0.1:4000/', // 代理目标
  changeOrigin: true, // 支持跨域
  pathRewrite: {
    '^/api/': '/' //比如： /api/getStudents -->> /getStudents
  },
};
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(express.static(path.join(__dirname, 'public')));
//1创建代理服务器，必须 放到 处理静态资源之后
//2 放到处理路由资源之前
//4 注册代理服务器
// 3 创建代理服务器
const exampleProxy = createProxyMiddleware(options);
app.use('/api', exampleProxy);


app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());

app.use('/', indexRouter);
app.use('/users', usersRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;
